That wouldn't be Wauwatosa, Wisconsin, would it?

Anyway, here's a question I already have experience in. Just to add to what Ching-Ho said --

Be careful when removing the first strut, either side. Chances are the other side won't have enough strength to hold up the gate by itself. Frankly it's much easier to have a helper, preferably around 6 feet tall, for this procedure. I used a hammer to smack the strut socket off the ball mounting on the gate; then removing the other end by the headliner is easy. Look to see if there's any retaining clips on the sockets; unsnap and withdraw them first.

It is pretty key to have that other human hold up the gate when installing the new struts. (I would never publicly admit to having a jury-rigged stepladder prop fail and getting smacked across the bridge of the nose by a falling hatch; besides, I didn't even need stitches that might provide visual evidence of such a ridiculous mishap.) First install the end by the headliner, and the other socket end should line up with the ball on the hatch, so you can use a large slip-joint pliers to compress the joint together. If they still don't line up, note that the ball by the headliner is mounted on a bracket with slotted bolt holes. You could loosen those and make an adjustment if necessary.